Process for producing filaments from a raw material which has been solidified by theaction of solid, liquid, or gaseous media



June 9, 1936. H. ZIEGNER 2,043,722 PROCESS FOR PRODUCING FILAMENTS FROM A BAW MATERIAL WHICH HAS BEEN SOLIDIFIED BY THE ACTION OF SOLID, LIQUID, OR GASEOUS MEDIA I Filed June 29, 1955 Patented June 9, 1936 UNITED STATES PROCESS FOR PRO FROM A RAW MA BEEN SOLIDIFIED DUCING FILAMENTS TERIAL WHICH HAS BY THE ACTION SOLID, LIQUID, 0R GASEOUS MEDIA Heinrich Ziegner, Hagen, Germany Application June 29, 1935, Serial No. 29,182 3 Claims. (Cl. 18-54) This invention relates to the production of filaments from a fluid raw material that is solidified by the action of a solid, liquid, or gaseous medium. In the known processes, the material to be solidified is passed through a fine nozzle and emerges into a hardening liquid in which the filament solidifies. Under these conditions there is the difficulty of obtaining filaments that are of uniform thickness, for the mass as it leaves the nozzle is still quite fluid and is there subject to a certain tension. Furthermore, the known processes have the disadvantage that it is difficult to produce a perfectly uniform filament.

By means of the process according to the invention these disadvantages are avoided and considerable further advantages are secured by feeding the raw material under pressure if required, through a body, preferably tubular, the walls of which are perforated in the manner of a sieve or are porous or permeable by gas, and the operative medium is introduced, under higher pressure if required. through the walls of the preferably tubular body, and thus is caused to act on the raw material in such manner that solidification takes place during the passage through the tubular body. It will be understood that this does not exclude the possibility of passing the completely formed filament, after it leaves the small tube, freely through a medium which may solidify the filament still further.

In explanation of the process according to the invention, the course of the process is diagrammatically illustrated in the drawing.

Referring to the drawing, the solution e in the vessel dis the raw material for the filament which is to be solidified. This material is shaped by extrusion under a moderate pressure through a small, highly porous porcelain tube a, the middle part of which passes through and is surrounded by a body of liquid 0 contained in a vessel b. The pressure of the liquid c upon the tube a may be increased by the provision of a standpipe or column b1. By reason of the porosity of tube a the hardening liquid (the liquid 0) forces its way through the tube walls and comes into contact with the shaped body of liquid e to be solidified, and spreads in a uniform film over the whole surface of the said shaped body. Thus the contents of the small tube are solidified to form the filament J. The hardening liquid issuing from the pores covers the inner surface of the small tube with a uniform film, and this causes the filament within to slide down automatically when the small tube stands vertically.

Within the small porous tube the quantity of liquid to be solidified is always the same, when the composition is the same (and this also applies to the thickness of the filament), the quantity of liquid being only dependent upon the cross-section of the tube, so that thus with the same composition and the same small tube the filament is always the same in thickness. Thus the thickness of the filament is dependent,

firstly, upon the composition of the mixture and,

secondly, upon the cross-sectional area of the small tube.

It thus becomes possible, by varying the mixture, that is to say (for example) by changing the percentage of the solid constituents or otherwise altering the viscosity, to increase or decrease the cross-section of the finished filament within certain limits. Furthermore, it will be understood that a thicker filament may be produced by the use of a tube of larger cross-section. In the process according to the invention, therefore, the further advantage is obtained that raw materials of different viscosities (for example, even quite thin liquids) may be used.

Particularly good results are obtained with the process according to the invention if the raw material be a coagulating substance, particularly a latex dispersion, and if an organic acid be chosen as the hardening medium. The process according to the invention may, however, also be employed for any other raw material that can be hardened. Thus, for example, the raw materia. may consist of polymerization products, such as a mixture of phenol and aldehyde, and the active medium may be any acid. Finally glue-like raw material may be treated by the process of the invention. in which case 'aldehydes and particularly formaldehyde may be the liquid that is employed to effect the hardening of the material of the filament.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. The method herein described of producing a filament from a fluid raw material that becomes solid under the contact of another medium, which consists in shaping the fluid raw material within a permeable wall and causing a solidifying medium penetrating such wall to come into contact with the fluid material shaped within.

2. The method herein described of forming a filament which consists in shaping a fluid body within a porous tube and causing a hardening medium penetrating the tube to engage the body shaped within it.

3. The method herein described of forming a filament which consists in forcing a fluid body under pressure into and through a tube of porous walls and causing a hardening medium penetrating such walls to gain access to the body so advancing through the tube.

HEINRICH ZIEGNER. 

